NEW YORK -- The Yankees are going to have some tough decisions to make in the next few days, and Lyle Overbay is making it even tougher on them.

With Mark Teixeira coming back from a right wrist injury and playing a pair of rehab games on Wednesday and Thursday at Double-A Trenton, his return at first base is looming like a shadow over Overbay, who has more than ably manned that position.

"It doesn't matter," Overbay said on Tuesday night after his sixth-inning single accounted for the go-ahead run in a game the Yankees ultimately lost to the Mets, 2-1, at Citi Field. "It's always been hanging over my head. I just want to enjoy what we're doing here and help this team win. I'm just taking it day by day and we'll see what happens. It will work out."

Overbay's single off Mets rookie Matt Harvey was his ninth go-ahead RBI for the Yankees this season, tying him with Travis Hafner for the club lead in that category. The run stood until the bottom of the ninth, when the usually lights-out Mariano Rivera blew his first save of the season and only the 74th in the regular season during a stellar 19-year career.

Overbay was signed almost immediately after the Red Sox released him on March 26. Teixeira tore the tendon in the wrist while hitting with a weighted bat off a tee one day after joining Team USA in preparation for the World Baseball Classic. It was feared at the time that Teixeira might need season-ending surgery and that possibility still lingers.

But Teixeira has worked his way back to this point and there's some talk that if he clears the hurdle of the next two rehab games, the switch-hitter could be activated in time for Friday night's opener of a three-game series against the Red Sox at Yankee Stadium.

The two teams, beset by injuries and in quasi-rebuilding modes, have surprised many by battling for the lead in the American League East during the opening two months of the season. First, there's the matter of two more games against the Mets this week as the Subway Series shifts to the Stadium on Wednesday night.

If Teixeira is deemed ready, that's when decisions need to be made. The Yankees have the lefty-swinging Hafner to use at designated hitter and as a backup first baseman. Overbay, also a lefty hitter, is a similar type of player.

In addition, the Yankees have the righty-swinging Kevin Youkilis in Trenton on a rehab assignment. He'll undoubtedly be slotted back in at third base with David Adams heading back to the Minor Leagues.

Yankees manager Joe Girardi said prior to the game that Youkilis and Teixeira had taken five at-bats apiece in an extended spring training game on Tuesday in Florida and were ready to take the next step.

Both players could be activated as early as Friday night.

"I have said all along it depends on how they feel, physically and mentally, is when you decide to activate them," said Girardi, adding that Teixeira would certainly play every day at first base when he is ready.

Girardi said that he and members of baseball operations, including general manager Brian Cashman, have had preliminary discussions about how they will shuffle the 25-man roster, but no hard decisions have been made as of yet.

"I mean, we go through those discussions every once in awhile, but I've also said you worry about it when it's the time. Other things have happened in the past when you're all worried about it and people want you to talk about it, so until we get to that day we won't say anything. There are ideas, obviously, but things can change real quick around here."

Make no mistake about it, though. Overbay is clearly aware that he's on the bubble. He's made the most of his 49 games in pinstripes, hitting .251 with eight homers and 29 RBIs. His RBI total is second only to Robinson Cano for the Yankees at the moment.

In recent days, Overbay has made it even tougher on upper management when he started the game-tying rally on Saturday by taking a walk against Rays closer Fernando Rodney and won the game with an 11th-inning homer. And then there was Tuesday night's RBI single against Harvey.

"It's all good," Overbay said, when asked about the pending activation of Teixeira. "I just want to enjoy it. I don't want it to affect the experience I'm having. So I try not to worry too much about it."

It's not as if the 36-year-old Overbay hasn't been at this juncture recently in his nomadic 13-year career. Since Aug. 5, 2011, when he was released by the Pirates, Overbay has been released three times and granted free agency twice while signing with four different clubs.

Two weeks after his release by the Pirates, Overbay was actually in the driveway of his house washing the car when D-backs general manager Kevin Towers called to ask him if he wanted a second go-round in Arizona. Overbay actually hit .286 for a club that won the National League West and lost to the Brewers in the first round of playoffs.

When he was released by the Red Sox this spring, Overbay said his agent immediately called the Yankees.

He's been a solid contributor ever since.

"It's fun. It's fun to come to the ballpark. Obviously the winning helps," he said about a team that is 30-21 despite three consecutive losses. "We have fun. But when we get on the baseball field, we're all business. Expectations to win are always good, too."

Now the question is, what will the Yankees do? Overbay is again on the edge and he is making that decision very tough for them.